Sealer for packaging foodstuffs and the like



5 Sheets-Sheet 1 ATTORNEYS E. M. BICKHAM ET AL SEALER FOR PACKAGING FOODSTUFFS AND THE LIKE EULAND SAMUEL 5A, MMA W Nov. 4, 1969 Filed Dec. 27, 1967 Qww Q um \QI SEALER FOR PACKAGING FOODSTUFFS AND THE LIKE E. M. BICKHAM ET Nov. 4, 1969 5 Sheets-Sheet 2 Filed Dec. 27

EULAND M. BICKHAM 6 SAMUEL ROSENFELD &4. A T ORNEYS Nov. 4, 1969 E. M. BICKHAM ET SEALER FOR PACKAGING FOODSTUFFS AND THE LIKE 5 Sheets-Sheet 5 Filed Dec.

- ws w ATTORNEY NOV. 4, 1969 E, BlCKHAM ET AL SEALER FOR PACKAGING FOODSTUFFS AND THE LIKE Filed Dec. 27, 1967 5 Sheets-Sheet 4 INVENTORS EULAND M. BICKHAM 46 SAMUEL ROSENFELD ATTORNEYS United States Patent 3,475,880 SEALER FOR PACKAGING FOODSTUFFS AND THE LIKE Euland M. Bickham, North Babylon, and Samuel Rosenfeld, Islip Terrace, N.Y., assignors to Instrument Systems Corp., Huntington, N.Y., a corporation of New York Filed Dec. 27, 1967, Ser. No. 693,976 Int. Cl. B65!) 7/16, 53/02, 61/06 U.S. Cl. 53-141 14 Claims ABSTRACT OF THE DISCLOSURE A sealer for providing over a material such as foodstuff in a tray a sheet of heat shrinkable film which shrinks beneath a lip of the tray. The sealer has a support means which supports a tray in a position where the support means extends rearwardly, forwardly, and laterally beyond both sides of the tray, and a supply means is located rearwardly of the tray to supply a sheet of heat-shrinkable film to be drawn by the operator forwardly over the tray resting on the material therein and engaging the support means at an area which surrounds the tray. A manually operable means is displaceable from an upper rest position where it is located at least in part over the tray downwardly along a working stroke to an operating position located approximately at the elevation of the tray, and this manually operable means carries a heating means which burns through the film at the area of the support means which surrounds the tray to provide the film with a heated edge which shrinks automatically beneath the lip of the tray. A cutting means is carried by the support means rearwardly of the tray and responds to movement of the manually operable means along its working stroke for cutting 'from the film a section which is then acted upon by the heating means.

CROSS REFERENCE TO RELATED APPLICATION After a package has been formed with the sealer of the present application it is directed through a heat tunnel shown in copending application Ser. No. 693,975 filed on Dec. 27, 1967.

BACKGROUND OF THE INVENTION The present invention relates to a sealer for covering a material, such as foodstuffs, in a tray with a heat-shrinkable film which shrinks beneath a lip of the tray.

In the packaging of material such as foodstuffs, it is conventional to locate the materials in trays which have open tops where the material is accessible. The material together with the tray are conventionally overwrapped with a film which passes completely around the package. In addition to the inconvenience and time involved in providing such a complete overwrap, the view of the material in the tray is obstructed and a considerable cost is involved in supplying the film which is necessary for such overwrapping. In addition, the manipulations involved in such conventional packages requires an experienced operation, and the known structures are complex, expensive, and difiicult to clean. Of course, when dealing with foodstuffs it is essential to provide a construction which can easily be cleaned for sanitary purposes.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a sealer which will avoid the above drawbacks.

In particular, it is an object of the invention to provide a sealer which will eliminate the necessity of completely overwrapping the tray with the material therein.

3,475,880 Patented Nov. 4, 1969 In particular, it is an object of the invention to provide a sealer which can eliminate to of the film conventionally required to overwrap packages according to the methods used most commonly at the present time in installations such as supermarkets and central packaging facilities.

In addition, it is an object of the present invention to provide a sealer which will offer an unobstructed view both of the top and the bottom of the package, with considerable advantages to the consumer as a result of the clear visibility of the material from all sides thereof.

Furthermore, it is an object of the present invention to provide a sealer which can readily be operated manually by an inexperienced operator.

Also, it is an object of the invention to provide a sealer which can complete the operations on any one package within an extremely short time, usually from 4-8 seconds, depending upon the dexterity of the operator. Thus, it is an object of the invention to reduce the time conventionally required in packaging operations so that a relatively large output of packages can be achieved in a relatively short time, and thus considerable economies are obtained when dealing with a large number of packages.

In addition, it is an object of the invention to provide a construction which can easily be assembled and disassembled for cleaning purposes and which is composed of materials which are very easily cleaned, so that the highest standards of sanitary conditions can be maintained with the sealer of the invention.

Also, it is an object of the present invention to provide a sealer which is of a relatively small size, taking into consideration the job which it performs, which is relatively inexpensive, and which at the same time is composed of rugged components which will operate very reliably.

Also, it is an object of the present invention to provide a sealer which can readily be adapted to handle packages of different shapes and sizes.

Furthermore, the objects of the present invention include the provision of a sealer which is capable of handling heat-shrinkable films of different widths while at the same time positioning the film so that it can conveniently be manipulated by the operator.

In accordance with the invention the sealer includes a support means for supporting a tray in a position where the support means extends forwardly, rearwardly and laterally beyond all sides of the tray. A supply means is situated to the rear of the tray for supplying a sheet of heat-shrinkable film to be drawn by the operator over the material in the tray, resting on this material and extending therefrom to an area of the support means which surrounds the tray. A manually operable means is located at least in part in a rest position over the tray on the support means and is manually displaceable downwardly along a working stroke to an elevation where the manually operable means is located approximately at the elevation of the tray. A cutting means is carried by the support means to respond automatically to movement of the manually operable means downwardly along its working stroke for cutting across the film to provide a separate section thereof which rests on the material in the tray and engages the area of the support means which surrounds the tray. The manually operable means carries a heating means which during movement of the manually operable means along its working stroke burns through the film all the way around the tray to provide the film with a heated edge which automatically shrinks beneath a lip of the tray.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a partly fragmentary and partly sectional top plan view of a sealer according to the invention;

FIG. 2 is a fragmentary sectional side elevation of the sealer of FIG. 1 taken in a vertical plane extending longitudinally of the sealer substantially centrally therethrough;

FIG. 3 is a fragmentary sectional side elevation showing the coacting parts of the manually operable means and cutting means of FIG. 2 in a rest position thereof and at a scale which is enlarged as compared to FIG. 2;

FIG. 4 shows the parts of FIG. 3 during movement of the manually operable means downwardly along its working stroke at the instant just after the cutting means has cut through a sheet of film;

FIG. 5 shows the structure of FIGS. 3 and 4 during the continued downwardly movement of the manually operable means along its working stroke while the cutting means has returned to its initial position;

FIG. 6 is a transverse sectional elevation taken along line 6-6 of FIG. 1 in the direction of the arrows and showing at an enlarged scale the coacting components of the manually operable means and cutting means at one side of the sealer;

FIG. 7 is a fragmentary side elevation taken along lines 7-7 of FIG. 1 in the direction of the arrows, and showing a latching structure of the sealer;

FIG. 8 is a fragmentary sectional elevation taken along line 8-8 of FIG. 1 in the direction of the arrows and showing at an enlarged scale structure for removably mounting a heating means on the manually operable means;

FIG. 9 is a fragmentary sectional plan view of the structure of FIG. 6 taken along line 9-9 of FIG. 6 in the direction of the arrows; and

FIG. 10 is a fragmentary sectional elevation of a platen assembly of the support means taken along line 1010 of FIG. 2 in the direction of the arrows and showing the structure on an enlarged scale as compared to FIG. 2.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings, the sealer disclosed therein has a support means 22. This support means 22 includes a bottom wall 24 which extends completely across the sealer and from the front to the rear end thereof. The bottom wall 24 is integral at its side edges with a pair of upstanding side walls 26 of the support means 22. At the region of the forward end of the support means these side walls 26 are integrally connected at their upper edges with inwardly directed horizontal flanges 28 which are shown in plan in FIG. 1. The bottom wall 24 carries a plurality of upwardly directed buttons 30 which are formed with transverse slots extending therethrough to receive the bottom ends of coil springs 32 which surround buttons 30 and extend upwardly therefrom. For example, four of these buttons 30 and coil springs 32 may be provided at the corners of a rectangular area.

The top ends of the coil springs 32 receive slotted buttons 34, respectively, which are similar to the buttons 30 and which are fixed to and project downwardly from a plate 36 which is fragmentarily illustrated in FIG. 10. This plate 36 thus rests on the springs 32 and the plate 36 extends between the inner side edges of the flanges 28 of the support means. The side edges of the plate 36 are spaced slightly inwardly from the inner sides edges of the flanges 28 so that the plate 36 can be displaced vertically. This plate 36 carries at its upper surface a platen 38, and the outer peripheral edge of the plate 36 extends beyond the peripheral edge of the platen 38. A sheet of Teflon 40 covers the platen 38 and extends around the peripheral edge of plate 36. An elongated channel 42 extends completely along the peripheral edge of the plate 36 and receives this peripheral edge in its interior with the sheet 40 extending around this peripheral edge, so that in this way the sheet 40 is clamped to the plate 36 and covers the platen 38. As is shown most clearly in FIG. 2, the channel 42 is composed of a plurality of channel sections which abut each other in end-to-end relation, and each channel section has adjacent to its end a downwardly directed lug 44- connected to one end of a coil spring 46 the opposite end of which is connected to the lug 44 of the adjoining channel section, so that in this way the sections of the channel 42 are pulled into engagement with each other. As a result of this construction it is possible very easily to pull apart the sections of the channel 42 so that it can be removed easily for cleaning purposes, and also if enables the sheet 40, platen 38, and plate 36 to be disassembled from each other. Of course, the entire assembly of the platen 38 with the sheet 40, the plate 36 and the channel assembly 42 can very easily be lifted from the springs 32 for cleaning purposes.

The entire structure is supported at a suitable elevation by way of a plurality of legs 48 fixed to and extending downwardly from the lower surface of the wall 24, and one of these legs is visible in FIG. 7. The above-described support means 22 which includes the platen assembly is designed to support a tray T with a suitable material M therein, this material being any foodstuffs, for example. The tray T has a peripheral lip L at its upper edge. It will be noted that the support means when supporting a tray T extends both forwardly and rearwardly as well as laterally beyond both sides of the tray.

While the plate 36 and the platen 38 as well as the sheet 40 can be uninterrupted over their entire area so as to provide a perfectly flat top service for a tray, it is also possible to adapt the structure for use with relatively deep trays. For this purpose the platen 38 and the plate 36 therebeneath are formed with aligned octagonal openings 48, having the configuration shown in FIG. 1, and in this case the sheet 40 is provided with a central opening and with tabs which extend around the edges of the platen 38 and the plate 36 at the aligned openings 48 thereof, these tabs being fixed to the underside of the plate 36 in any suitable Way. At the underside of the plate 36 there is provided an elongated support 50, shown most clearly in FIG. 2, this support having upper ends fixed to the underside of plate 36, so that in this way a relatively deep tray can extend through the openings 48 to be carried by the support 50 with the lip of the deep tray located at about the same elevation as the lip L for the tray T in FIG. 2. With this construction an octagonal plate can be situated within the openings 48 resting on the upper ends of the support 50 with the upper surface of this filler plate flush with the upper surface of the sheet 40 which surrounds the openings 48, so that either a tray as shown in FIG. 2 can be supported on such a filler plate or the filler plate can be removed and a relatively deep tray can be mounted on the support 50. Thus, the support means is capable of being adapted to trays of different depths.

The support means carries any desired holders for holding the trays in the required positions, particularly trays which rest on the upper surface of an uninterrupted sheet 40, and for this purpose the sheet is provided with openings through which a rear circular opening 51 and a pair of elongated grooves 54 are accessible. The opening 51 and grooves 54 can also be provided in a filler plate which fills the openings 48. The holder for the tray T simply has a rear projection received in the opening 51 and a pair of forward projections received in the grooves 54, so that in this way the holder can be reliably located in the position to receive a tray T, this holder having upwardly directed elements at its sides which engage the exterior side surfaces of the tray T beneath the lip L thereof so that in this way a tray can be properly situated on the support means.

The sealer is also provided with a manually operable means 52 having an upper rest position which is shown in FIG. 2, and this manually operable means 52 can be displaced by the operator downwardly from the rest position thereof shown in FIG. 2 along a working stroke where the manually operable means becomes situated approximately at the elevation of the tray T. The manually operable means 52 has a pair of side arms 54 provided at their bottom edges with inwardly directed flanges 56 which are spaced from each other by a distance greater than the distance between the side walls 26 of the support means 22, with these side arms 54 being situated equi-distantly from a central vertical plane which extends longitudinally and centrally through the support means 22, so that during lowering of the manually operable means 52 the side arms 54 will clear the side walls 26 which will become situated between the side arms 54 of the manually operable means, and one of the side arms 54 is shown in its lower operating position in FIG. 7 which shows the wall 26 behind the side arm 54.

The side arms 54 are fixed, as by welding, at their rear ends to a pair of hollow tubular enclosures 58 which respectively have outer closed ends and inner open ends directed toward each other, and these enclosures are mounted on a through-rod 60 which extends horizontally through the enclosures 58 and through suitable bearings carried by the side walls 26 of the support means 22, as shown most clearly in FIG. 9. The ends of the rods 60 are threaded to receive cap nuts 62 which engage suitable lock washers situated between the outer end walls of the tubular enclosures 58 and the nuts 62, respectively.

A spring means is provided for yieldably maintaining the manually operable means 52 at its rest position which is illustrated in FIG. 2, where the manually operable means is located in part over a tray T on the support means 22, and this spring means includes a pair of torsion springs 64 respectively situated within the tubular enclosures 58. These torsion springs 64 respectively have inner ends 66 extending through openings formed in the side walls 26 of the support means. At their outer ends the torsion springs 64 respectively extend around pins 68 which are fixed to and extend inwardly from the outer end walls of the tubular enclosures 58. In this way the springs 64 are capable of counter-balancing the weight of the manually operable means and maintaining the latter at the rest position illustrated in FIG. 2. Thus, the shaft 60 defines an axis of turning for the manually operable means, and this axis about which the manually operable means swings extends horizontally across the support means to the rear of the structure thereof which carries the tray T.

The side arms 54 are interconnected at their front ends by a transverse rod 70 made of wood, for example, so that it is not a good conductor of heat, and thus the operator standing at the front of the sealer can readily grasp the transverse rod 70 in order to lower the manually operable means 52 in opposition to the spring means 64 to the operating position as shown in FIG. 7.

The pair of side arms 54 of the manually operable means 52 are also interconnected by a transverse rod 72 situated just behind the manually-engageable rod 70, and this rod 72 is supported for swinging movement about its axis in the side arms 54. The rod 72 carries a pair of latch members 74 having the substantially L-configuration shown in FIG. 7 and having at their upper ends outwardly extending tabs 76 extending across and over the top edges of the side arms 54. The latch members 74 are fixed to the rod 72 for swinging movement therewith, and they are close enough to the handle 70 so that the operator can engage either latch member with either hand in order to swing both latch members and the rod 72 therewith. At their upper front ends the side walls 26 carry a pair of outwardly laterally extending projections 78, and when the tabs 76 are swung forwardly toward the handle 70 the latches 74 will clear these projections 78. However, when the manually operable means is in its operating position as shown in FIG. 7, the operator can easily swing the latch members to the position shown in FIG. 7 where their lower rearwardly directed legs are situated beneath the pins 78, so that the springs 64 will urge the latches into engagement with the pins 78, thus enabling the operator to have the manually operable means maintained in its operating position for the required period of time, which may only be a few seconds, after which the operator can easily return the latch members to their forward positions where they will clear the projections 78, and now all the operator needs to do is release the handle 70 so that the springs 64 will return in a fully automatic manner the entire manually operable means 52 and the structure carried thereby to the rest position in FIG. 2.

A supply means 80 is provided for supplying to the operator a sheet of heat-shrinkable film S, made of a plastic such as polyvinyl chloride or polyethylene, for example, and this clear, transparent sheet is capable of being pulled by the operator forwardly over the material M to rest thereon as well as to engage the area of the support means which surrounds the tray T, as will be apparent from the description below. The supply means 80 includes a pair of lateral stanchions 82 respectively having a bottom inwardly directed flanges 84 (FIG. 1) fixed to the upper surface of the wall 24 of the support means 22, in any suitable way. These rugged stanchions 82 are provided at their top ends with notches for receiving a transverse roll-supporting rod 86. The stanchions 82 which are in lateral alignment with each other extend upwardly and forwardly, and at their lower rear end portions they are provided with downwardly and forwardly inclined notches into which a lower roll-support ing rod 88 can he slipped. These rods respectively carry slidable sleeves 90 capable of being fixed at suitable locations along the rods by wing screws 92. The sleeves 90 can extend into the opposed open ends of a core 94 which carries a roll 96 of the heat-shrinkable sheet material S. This structure which supports a lower roll 96- is fragmentarily illustrated in FIG. 1, and in the same way an upper roll 98 can be supported on the upper rod 86. A guide roller 100 extends between and is turnably carried by the stanchions 82 and is supported for the free rotary movement thereby, so that when the sheet S is taken from the upper roll 98, the sheet can be guided around the roller 100 and then downwardly to the structure of the sealer which is described below. The sheet S from the upper roll 98 is shown extending in this way around the roller 100 in FIG. 2. When the sheet is taken from the lower roll 96, the guide roller 100 need not be used and the sheet material can be led from the lower roller 96 directly to the additional structure situated forwardly of the supply means 80. In this way it is possible to mount on the rods 86 and 88 rolls of different widths so that the operator has a choice as to the width of sheet material which is to be used for a particular tray,

The supply means 80 further includes a pair of side brackets 102 which have lower inwardly directed flanges 104 fixed to the top surface of the bottom wall 24 of the support means, and these side brackets 102 are situated adjacent but spaced inwardly from the side walls 26 of the support means. At their upper ends the brackets 102 have rearwardly directed extensions which support be tween them a guide roller 106 around which the sheet material S is guided in the manner shown in FIG. 2, and this roller 106 is supported for free rotary movement by the brackets 102. While the sheet from the upper roll 90 extends beneath and around the roller 106, a sheet from the lower roll 96 can extend either over or under the roller 106. From this roll 106 the sheet S extends over a forward guide roller 108 supported for free rotary movement by the brackets 102 at the lower ends of a pair of curved slots 110 which extend upwardly and then rearwardly from the forward guide roller 108. These slots accommodate just above the roller 108 a second forward roller 112 which can be displaced upwardly along the curved slots 110 to the rear ends thereof. The rollers 108 and 112 can simply have reduced ends extending through the slots 110. When the sheet material is initially threaded through the supply means the upper roller 112 is displaced to the upper ends of the slots 110 so as to be maintained spaced from the lower roller 108, and in this way the sheet material can easily be threaded between the rollers 108 and 112, after which the roller 112 is returned to its position shown in FIG. 2 where it rests by gravity on the sheet material holding the latter in the nip between the rollers 108 and 112.

As is shown most clearly in FIG. 6, the lower forward roller 108 is formed adjacent the brackets 102 with a pair of annular grooves 114 in which a wire spring 116 is coiled through a few convolutions, the free end of the wire spring 116 extending forwardly beyond the roller 108 to provide adjacent the opposite ends thereof a pair of sheet-supporting fingers 116 supporting the free end of a sheet in the manner shown most clearly in FIGS. 3 and 5. This finger assembly 116 includes downwardly extending Wire spring portions which are curved inwardly toward each other and which are fixed to the opposed ends of an elongated counterbalancing rod or weight 118, so that while the entire finger assembly 116 is capable of swinging freely around the rod 108 in the grooves 114 thereof, when there are no other forces acting upon the finger assembly it will automatically assume by gravity the condition shown in FIGS. 3 and where it will support the free edge of a sheet at a position convenient for grasping by the operator to be pulled forwardly in the manner indicated by the arrow 120 in FIG. 3. The counterbalancing rod 118 extends completely across the space between and is connected to the bottom lower ends of the wire springs which form the finger assembly 116, and in this way a finger assembly which is automatically oriented gravitationally is provided for conveniently supporting the sheet material in a position to be grasped by the operator so as to be conveniently pulled forwardly over the tray T. p

The support means 22 of the sealer carries to the rear of the platen part of the support means which carries the tray T a cutting means 122 the operation of which is illustrated in FIGS. 3-5 and details of which are illustrated in FIGS. 6 and 9 as well as FIGS. 1 and 2.

The cutting means 122 includes a stationary cutting blade 124 having an upwardly directed cutting edge 126 and fixedly carried in any suitable way by a transverse plate 128 of the support means, this plate being fixed to and extending upwardly from the bottom wall 24 of the support means, these latter details all being shown most clearly at the lower right portion of FIG. 6. The support plate 128 extends transversely across the sealer and the same is true of the cutting blade 124 which is situated just forwardly of the finger assembly, as indicated in FIGS. 2-5.

The stationary side walls 26 of the support means carry a stationary through-rod 130 of the support means and this through-rod 130 is fixed to the side walls 26 as by the nuts 132 and lock-washers 134 one of each of which are illustrated in FIG. 9. This stationary throughrod 130 of the support means 22 serves to support for rotary movement a pressure pad assembly 136 in the form of an elongated hollow rectangular member 138 having an open bottom through which the blade 124 extends into the interior of this member 138 when the pressure pad assembly 136 is in its rest position shown in FIGS. 2 and 3. The hollow member 138 has a top wall formed with an elongated slot 140 passing therethrough and registering with the blade 124 so that when the pressure pad assembly 136 is lowered, in a manner described below, the slot 140 will move downwardly with respect to the blade 124 so that the upper edge thereof will be situated higher than the slot 140. The elongated rectangular hollow enclosure 138 of the pressure pad assembly 136 is fixed at its opposed ends to a pair of side arms 142, respectively, and these side arms 142 are supported for free rotary movement on the rod 130 in the manner shown in FIG. 9 for one of the side arms 142. The side arms 142 are mounted on a pair of rings 144, respectively, which carry the bearings 146, respectively, which directly engage the rod 130. A spring means is provided for urging the pressure pad assembly 136 to the rest position thereof illustrated in FIG. 3 where its upper slotted wall is situated higher than the blade 124, and this spring means takes the form of a torsion spring 148 surrounding the spring 144, having an inner end extending into an opening 150 of side arm 142 and having an outer end pressing against a cross-pin 152 which extends through a bore of the rod 130 and which is fixed to the latter. This structure which is shown in detail in FIG. 9 for one of the side arms 142 is repeated for the other side arm 142 of the pressure pad assembly 136, and these springs 148 urge the pressure pad assembly in a counterclockwise direction, as viewed in FIG. 3, around the rod 130.

Just inwardly of the side walls 26 of the support means 22 the rod 60 which supports the manually operable means 52 for swinging movement carries a pair of elastic sleeves 154 made of soft rubber or the like and maintained in position on the rod 60 in any suitable way as by snap-rings 156 shown in FIG. 9. Thus, the rod 60 is provided in this way adjacent to the walls 26 with a pair of elastic covering members which act as stops for the side arms 142, respectively, of the pressure pad assembly. FIG. 3 shows the rear end of one of the side arms 142 engaging the elastic stop sleeve 154 which is carried by the rod 60. The spring means 148 urges the pressure pad assembly into engagement with the elastic stop 154 so that in this way the rest position of the pressure pad assembly 136 which is illustrated in FIG. 3 is determined.

The rod 130 also serves to support for swinging movement a hammer assembly 158 of the cutting means 122. This hammer assembly also has an elongated hollow enclosure 160 which has the cross-sectional configuration most clearly shown in FIGS. 3-5, and this hollow enclosure has a bottom wall 162 which is formed with an elongated slot 164 of the same length and size as the slot 140 and precisely registering with the latter during downward swinging movement of the hammer assembly 158 in a manner described below. The lower surface of the wall 162 fixedly carries a pair of strips 166 of rubber or the like which extend respectively along the edges of the slot 164. The slots 140 and 164 are slightly longer than the blade 124, and during the downward swinging of the hammer assembly 158 the slot 164 thereof also becomes located at an elevation somewhat lower than the top cutting edge of the blade 124, as indicated in FIG. 4, so that the blade 124 can also enter into the hollow elongated enclosure 160 of the hammer assembly 158 through the registering slots 140 and 164.

The elongated enclosure 160 of the hammer assembly 158 is also fixed at its outer ends to a pair of side arms, and these side arms 168 are formed with aligned openings through which the rod 130 passes. The side arms 168 are situated outwardly of the side arms 142, respectively, of the pressure pad assembly, and they are also supported for free swinging movement about the stationary rod 130 by way of the bearing assembly 170 shown in FIG. 9, this bearing assembly being duplicated at the other end of the rod 130 where the other arm 168, which is not shown in FIG. 9, is located.

The spring means which includes the spring.148 for locating the pressure pad assembly 136 in its rest position also includes a torsion spring 172 for situating the hammer assembly 158 in its rest position indicated in FIG. 3. This torsion spring 172 surrounds the bearing assembly 170 and has an inner end 174 engaging an end of the cross pin 152 opposite from the end thereof engaged by the spring 148 and an outer end 176 extending through an opening in the side arm 168. This spring structure 172 is repeated at both ends of the rod 130 and coacts with both side arms 168 to urge the hammer assembly 158 to the rest position thereof illustrated in FIG. 3. At their rear ends the arms 168 of the hammer assembly fixedly carry perpendicularly extending stop projections 178 which are also urged into engagement with the elastic stop sleeves 154 in order to determine the rest position of the hammer assembly 158.

Thus, it will be noted that with the above-described structure the pressure pad assembly 136 and the hammer assembly 158 have a common swing axis defined by the axis of the stationary rod 130, and in addition their rest positions are determined by a common stop structure carried by the shaft 60.

The side arms 168 of the hammer assembly fixedly carry a pair of coaxial outwardly directed projections 180. The coaxial projections 180 which extend laterally from the side arms 168, respectively, may, for example, take the form of rollers freely turnable on pins 182 and retained thereon by snap rings 184, respectively, and these pins have inner headed ends 186 engaging lock washers 188, respectively, and threadedly carrying nuts 190 which engage the outer surfaces of the side arms 168 (FIG. 9), so that in this way the lateral projections 180 are maintained mounted on the side arms 168 of the hammer assembly 158.

The side arms 54 of the manually operable means 52 are situated outwardly beyond the side arms 168, respectively, and at their rear regions, in the Vicinity of the tubular enclosures 58, these side arms 54 carry freely swingable pawls 192. For this purpose the side arms 54 carry a pair of coaxial pins 194 extending through coaxial openings of the side arms 54 and each carrying a spacer 106 and a washer 198 between which each paw 192 is freely swingable, The pin 194 is provided with an inner head 200 and at its outer threaded end carries a cap nut 202 which engages a lock washer 204, and when the structure is fully assembled the pawls 192 are freely swingable about a common axis and are respectively situated at both of the side arms 54 just inside the latter.

The configuration of the pawls 192 are clearly apparent from FIG. 3 where one of the pawls is illustrated. It will be noted that each pawl has a relatively large portion 206 situated forwardly of the pin 204 and tending by gravity to swing the pawl in a clockwise direction, as viewed in FIG. 3, so that the pawls are gravitationally maintained in their positions shown for the pawl 192 of FIG. 3. The inwardly directed flanges 56 at the bottom edges of the side arms 54 are notched at the front edges of the pawls 192 so as to form stop edges 208 limiting the clockwise swinging of the pawls 192 to the position shown in FIG. 3.

At their opposite ends the pawls 192 are provided with rearwardly directed and inwardly angled fingers 210, and is particularly apparent from FIGS. 6 and 9, the lateral projections 180 of the hammer assembly respectively extend through the vertical parallel longitudinal planes in which the rear fingers 210 of the pawls 192 are located.

The above-described cutting means 122 operates in the following manner:

It will be noted from FIG. 3 that when the sheet S rests on the finger assembly 116 in readiness to be grasped by the operator to be pulled forwardly in the direction of the arrow 120, the sheet S extends between the pressure pad assembly 136 and the hammer assembly 158. Thus, when the operator pulls the sheet forwardly to cover the material M in the tray T, the sheet S is situated above 10 the pressure pad assembly 136 and below the harmner assembly 158.

When the operator engages the handle 70 of the manually operable means 52 in order to swing the latter downwardly from its rest position along its working stroke, the pawls 192 which are carried by the side arms 54 of the manually operable means 52 will of course swing downwardly with the side arms about the axis defined by the rod 60. As a result the common axis of the pawls 192 defined by the pins 204 which carry the latter will describe part of a cylinder whose axis coincides with the axis of the rod 60, and in this way the pawls 192 will swing downwardly about the shaft 60 from the position of FIG. 3 into the position of FIG. 4. When the hammer assembly 158 is in its rest position determined by engagement of its rear projections 178 with the stop sleeves 154, the lateral projections 180, which necessarily swing about the axis of the rod 130, are spaced from the axis of the shaft 60 by a radial distance which is somewhat greater than the distance of the rear tips of the fingers 210 from the axis of the shaft 60, so that during the downward Swinging movement of the manually operable means these fingers 210 will necessarily engage the lateral projections 180 of the hammer assembly 158, and in this way the pawls 192 serve to transmit the movement of the manually operable means 52 to the hammer assembly 158 of the cutting means 122, and thus the cutting means 122 is automatically actuated in response to displacement of the manually operable means 52 downwardly along its working stroke.

When the inwardly angled rear fingers 210 of the pawls 192 engage the lateral projections 180, respectively, the hammer assembly 158 is constrained to turn downwardly with the manually operable means, and at this time the lateral projections 180 urge the pawls 192 to swing in a clockwise direction to engagement with the stop edges 208 of the flanges 56, so that the pawls 192 remain in the position shown in FIGS. 3 and 4 while transmitting the rotary movement of the manually operable means to the hammer assembly through the lateral projections 180 of the latter.

As the hammer assembly thus swings in a clockwise direction about the shaft 130, as viewed in FIG. 3, it will move down into engagement with the sheet S and will press the sheet downwardly against the pressure pad assembly 136 while the finger assembly 116 simply swings about the rod 108 inasmuch as the counterweight rod 118 permits the entire finger assembly 116 to swing freely about the rod 108 and only gravitationally maintains the finger assembly 116 in the position of FIG. 3 when a free end of the sheet S rests on the finger assembly 116. Thus, the finger assembly 116 will not resist the downward movement of the sheet into engagement with the pressure pad 136, and in this way the sheet S becomes clamped between the hammer assembly 158 and the pressure pad assembly 136, extending across and situated between the slots 164 and thereof, respectively.

The continued downward movement of the manually operable means in the direction of the arrow 212 of FIG. 4 will displace both the hammer assembly and the pressure pad assembly in opposition to the spring means formed by the springs 148 and 172 downwardly to the position shown in FIG. 4 where the slots of these assemblies are situated somewhat lower than the upper cutting edge 126 of the blade 124, so that in this way the blade 124 cuts through the sheet S which is lowered in this way across the cutting edge 126. In this way the cutting means will provide a separate section of sheet material S for covering the material M of the tray T.

It is to be noted that during the downward movement of the manually operable means 52, the fingers 210 of the pawls 192 swing along a cylinder whose axis coincides with the axis of the shaft 60, so that these fingers describe arcs of a predetermined radius, and this radius is substantially greater than the radius of swinging movement of the lateral projections which swing about the 1 1 axis of the shaft 130 at a substantially shorter radius. Therefore, while the fingers 210 are still well above a horizontal plane which contains the axis of the shaft 60', the lateral projections 180 are much closer to a horizontal plane which contains the axis of the rod 130, and thus the fingers 210 while engaging the lateral projections 180 are displaced forwardly with respect thereto. In the position of the parts shown in FIG. 4 the movement of the lateral projection 180 illustrated therein is substantially vertical in a downward direction while the movement of the finger 210 illustrated in FIG. 4 still has a substantial component toward the right, as viewed in FIG. 4. Therefore, when the manually operable means is displaced downwardly in the direction of the arrows 212 of FIG. 4 througha distance only slightly lower than the elevation thereof shown in FIG. 4, the fingers 210 and the lateral projection 180 will no longer be in motion-transmitting cooperation with each other, and the spring means formed by the springs 148 and 172 will be free to return the hammer assembly and the pressure pad assembly to their rest positions shown in FIG. 3. However, the manually operable means will still be able to continue its downward movement along its working stroke, as shown by the arrow 212 of FIG. 5 where the hammer and pressure pad assemblies are shown returned to their rest positions while the manually operable means 52 is shown at the region of the end of its downward working stroke. When the spring means 64 returns the manually operable means to its rest position, the upper edges of the fingers 210 of the pawls 192 will of course engage the lateral projections 180 of the hammer assembly 158, but this will only result in a slight swinging of the pawls 192 in a counterclockwise direction with respect to the side arms 54, and it will be noted that the stop edges 208 permit such swinging of the pawls to be carried out. After the fingers 210 pass the projections 180 during the return movement of the manually operable means 52, the center of gravity of the pawls 192 will return them to the positions shown for the pawl 192 of FIG. 3.

As is apparent from FIG. 4, the side walls 26 of the support means are provided along their top edges with notches 214 in order to provide clearance for the lateral projections 180. a

The manually operable means 52 carries a heating means 216 which is of endless configuration for extending around the tray T and engaging the film S to burn through the latter during movement of the manually operable means to the lower end portion of its stroke shown in FIG. 5. This heating means 216 is in the form, for example, of a light-weight aluminum casting 218 which has an elongated, electrically conductive tubular heater 220 embedded therein and extending along the same. While the rear transverse portion of the casting 218 is solid and of a trapezoidal cross section, the opposed elongated side portions and front transverse portion of the endless heating means 216 are of a thinner cross section and have at their inner and outer peripheries raised lips 222. These side and front portions also have an intermediate raised portion 224 in which the heating element 220 is embedded. In this way the amount of metal required for the casting 218 is reduced and at the same time a rigid casting is provided. At its lower surface the casting 218 is provided with a coating of Teflon (polytetrafluoroethylene), so that because of the inherent non-stick characteristics thereof and because of its high-temperature stability, this coating will prevent sticking of the polyvinyl chloride and polyethylene types of films to the lower surface of the heating means in the melted condition of these films. It is for the same reason that the Teflon sheet 40 is used to cover the platen 38.

The tubular heating element 220 is bent so as to conform to its final required configuration before it is embedded within the molten metal which is cast into the heating head 216. The heating element has terminals which protrude out of the top of the casting at the rear central portion thereof, and these terminals are connected by suitable electrical wires to a thermostat assembly 228 carried by the rear portion of the heating head and situated within a suitable protective housing. This thermostat assembly has a suitable control 230 accessible to the operator for adjusting the extent to which the heating means 216 is heated. Suitable conductors 232 lead from the thermostat assembly 228 (FIG. 1) to a male connector assembly 234 which is carried by the heating head and which has rearwardly directed prongs for a purpose referred to below.

The elongated side portions of the endless heating means 216 are each provided with a pair of integral outwardly directed projections 236 each of which is formed with a threaded bore 238, as shown in FIG. 8. This bore receives the threaded shank 240 of a screw 242 whose head is slidable in a hollow cylinder 244 having an inner end 246 formed with an opening through which a shank 248 of the screw 242, which is larger than the threaded shank 240 thereof, slidably extends in the manner shown in FIG. 8. A spring 250 is coiled about the larger, smoothsurfaced shank 248 of the screw 242 and engages the head of the latter so as to urge the hollow cylinder 244 to the right and the screw 242 to the left, as viewed in FIG. 8. As a result the end 246 of the cylinder 244 is urged toward the outer free end of each projection 236. The outer open end of the cylinder 240 is closed in any suitable way as by being received in the bore of a transverse handle 252 fixed by a set screw 254 to each hollow cylinder 244. A pair of these handles 252 are provided extending across a pair of cylinders 244 at the outer lateral portions of the heating means 216, and as a result of this construction it is possible for the operator to pull outwardly on the handle 252 to spread them apart from each other and thus expose portions of the shanks 248 which are adjacent the shanks 240.

Each of the side arms 54 of the manually operable means 52 is provided along its upper edge with a pair of L-shaped notches 256 for receiving the exposed portions of the shanks 248, respectively, and with this construction it is possible for the operator, while holding the handles 252 apart from each other in opposition to the springs 250, to slip the exposed portions of the shanks 248 first downwardly into the notches 256 at the forward ends thereof and then rearwardly along the notches to the rear ends thereof, so that in this way a structure is provided for releasably connecting a heating means 216 to the manually operable means 52.

As may be seen from FIG. 1, one of the arms 54 of the manually operable means 52 fixedly carries a female electrical connector assembly 258, and during the rearward displacement of the heating means 216 along the notches 256, the prongs of the male assembly 234 are received in the female connector 258. This connector assembly 258 is connected by electrical leads 260 to a control box 262 carried by the exterior surface of one of the side walls 26 of the support means 22, and this control box may house, for example, a switch for starting and stopping the sealer as well as a fuse. From the control box 262 an electrical lead 264 extends to be connected to any wall outlet or the like, so that in this way electrical energy can be supplied to the heating means 216.

Thus, with this construction the mounting of a heating means 216 on the manually operable means 52 will result automatically in electrical connection of the heating element 220 into a suitable electrical circuit, and the heating means will be maintained at a proper temperature during operation of the sealer.

A given sealer is provided with a plurality of heating heads 216 which are of sizes necessary to seal the containers which will be placed on the particular sealer. The heads are formed with openings in which the trays are adapted to be received, and the size of the inner periphery of each head 216 is sufiiciently great to conform to an industry standard container size plus a clearance around 13 the periphery of the tray T which allows for the proper amount of unburned film to lap around the container lip. The external dimensions of the heating means are determined by the amount of film required to cover the top of the container, engaging the material therein, draping downwardly from this material, which may be of varying heights, while still leaving enough, film to be melted by the heating means and to provide for a proper sealing band under the lip L of the tray.

When the heating means 216 burns through the film, the heated peripheral edge of the latter will forcefully shrink and automatically shrivel up beneath the lip of the tray T, the film moving in the direction of the arrow 266 of FIG. fromthe solid line position to the dotdash-line position shown in FIG. 5 beneath the lip L at the left end of the tray T. This forceful contraction of the heated periphery of the sheet material into a wrinkled, shriveled sealing band engaging the tray T beneath the lip L thereof is sufficiently great to reliably pull the sheet S over the material M and hold the sheet S on the tray T forming with the latter a package for the material M.

Thus, in order to operate the sealer of the invention all that the operator need do is place a tray with material therein on the support means. Then the sheet of heatshrinkable film is drawn over the tray and rests on the material therein while also engaging an area of the support means which surrounds the tray. The operator then displaces the manually operable means 52 downwardly so as to first actuate the cutting means to cut from the film a section thereof which remains in engagement with the material on the tray, and then the heating means 216 burns through the film all around the tray to cause the film to automatically shring itself up against the underside of the lip of the tray. The operator then releases the manually operable means which returns automatically to its rest position, whereupon the operator removes the tray so that it can then be further treated in a heat tunnel, which serves to draw the film even more tightly against the material in the tray.

It is apparent from the above-described structure of the heating means that it is a simple matter to exchange one heating means for another, so that the sizes of the heating means can be adapted to the size of the trays. The several heating means can be kept in a suitable rack with their female connectors 234 connected to suitable electrical structure which can be energized for any selected heating means prior to removal thereof from the rack to be placed on the manually operable means, and in this way it is possible to preheat a selected heating means just before it is placed on the manually operable means.

The downward movement of the manually operable means can be limited by suitable stops carried by the support means. The spring-supported platen assembly moves downwardly with the manually operable means 52 during the last part of the working stroke thereof.

All parts of the sealer are made of stainless steel or anodized aluminum, except for some bronze bearings, so as to offer a completely sanitary unit for the purposes of food handling.

It will thus beseen that the objects set forth above, among those made apparent from the preceding description, are efiiciently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. In a sealer for covering material in a tray with a heat-shrinkable film which shrinks beneath a lip of the tray, support means for supporting a tray with said support means extending forwardly, rearwardly, and laterally beyond all sides of the tray, manually operable means having a rest position located over said support means at least at that part thereof where the tray is located, said manually operable means being movable downwardly from its rest position along a working stroke to an operating position located approximately at the elevation of a tray carried by said support means, supply means situated rearwardly of a tray on said support means for supplying a sheet of heat-shrinkable film to be drawn by the operator over a tray resting on the material therein and engaging the support means at an area thereof which surrounds the tray, cutting means carried by said support means and responding to downward movement of said manually operable means along said working stroke thereof for cutting across the sheet of film rearwardly of the tray to provide a separate film section extending from the material in the tray to said area of said support means which surrounds said tray, and heating means carried by said manually operable means and being displaced thereby during movement along said working stroke to a location surrounding said tray and engaging the film for burning through the latter to provide the film with a heated peripheral edge which automatically shrinks beneath the lip of the tray.

2. The combination of claim 1 and wherein said support means includes a platen situated beneath and supporting the tray and providing said support means with said area surrounding the tray to be engaged by the film, and spring means supporting said platen for downward movement with said manually operable means during a final part of said working stroke thereof.

3. The combination of claim 1 and wherein said manually operable means is swingably connected to said support means rearwardly of the tray for swinging movement with respect to said support means about a substantially horizontal axis, and spring means coacting with said manually operable means for yieldably maintaining the latter in said rest position and for automatically returning said manually operable means to said rest position upon release of said manually operable means after the operator has moved said manually operable means in opposition to said spring means along said working stroke thereof.

4. The combination of claim 1 and wherein said cutting means includes an elongated cutting blade situated to the rear of a tray on said support means and having an upwardly directed cutting edge, a pressure pad assembly having a well formed with a slot aligned with said cutting edge and through which said upper cutting edge of said blade is adapted to extend upon downward movement of said pressure pad assembly, said pressure pad assembly having a rest position where said wall thereof is located at an elevation higher than said blade and being operatively connected to said support means for movement downwardly with respect thereto to a location situated beneath said cutting edge and upwardly with respect thereto to a rest position located above said cutting edge, and a hammer assembly located over said pressure pad assembly and having a wall directed toward said wall of said pressure pad assembly and also formed with a slot through which said blade is adapted to extend, said hammer assembly also being connected to said support means for downwardly movement with respect thereto to a location situated beneath said cutting edge of said blade, said supply means directing the sheet of heatshrinkable film beween said wall of said pressure pad assembly and said wall of said hammer assembly, spring means coacting with said assemblies for yieldably urging said pressure pad assembly to said location above said blade and said hammer assembly to said location over said pressure pad assembly, and said manually operable means coacting with said hammer assembly during movement of said manually operable means along said working stroke thereof for lowering said hammer assembly toward said pressure pad assembly to clamp a sheet of film between said walls of said assemblies extending across said slots thereof and to then lower both assemblies to a location where their walls are lower than said cutting edge, so that the latter extends through said slots and cuts through the film at the part thereof which extends across said slots. I

5. The combination of claim 4 and wherein both of said assemblies are operatively connected to said support means for swinging movement with respect thereto about a common axis.

6. The combination of claim 5 and wherein said manually operable means is operatively connected to said support means for swinging movement with respect thereto about an axis situated rearwardly of and extending parallel to said common axis.

7. The combination of claim 6 and wherein a rod extends along the axis about which said manually operable means swings and carries a resilient covering against which both of said assemblies are pressed by said spring means when said assemblies are returned to the locations where the walls thereof are situated above said cutting edge.

8. The combination of claim 7 and wherein each of said assemblies includes a pair of side arms extending rearwardly from said wall thereof and through which a pivot means at said common axis extends to pivotally support said arms and said assemblies for swinging movement about said common axis, said arms of said hammer assembly being situated outwardly beyond said arms of said pressure pad assembly and at least one of said arms of said hammer assembly carrying an outer projection which turns with said one arm about said common axis, said manually operable means having an arm situated outwardly of and extending along said one arm of said hammer assembly and swingably carrying a pawl part of which moves along a path intersecting said projection during swinging of said manually operable means along said working stroke thereof, the axis of swinging of said manually operable means providing for said pawl a path of movement which displaces it beyond said projection during continued downward movement of said manually operable means after said hammer assembly and pressure pad assembly have been lowered by engagement of said pawl with said projection to an elevation where said cutting edge of said blade extends upwardly through said slots, so that during the continued downward movement of said manually operable means along said working stroke thereof said pressure pad assembly and hammer assembly are returned by said spring means to their positions where said walls thereof are located over said blade.

9. The combination of claim 8 and wherein said arm of said manually operable means has a stop portion engaging said pawl to prevent swinging thereof with respect to said arm of said manually operable means while said pawl engages said projection to lower said hammer assembly and said pressure assembly therewith, said stop portion of said arm of said manually operable means releasing said pawl for swinging movement when said pawl engages said projection during return of said manually operable means to said rest position thereof.

10. The combination of claim 1 and wherein said heating means has an endless configuration for surrounding a tray and engaging the film which extends therefrom to burn through the film, said manually operable means having a pair of sidearms between which said heating means extends, and connecting means releasably connecting said heating means to said side arms of said manually operable means so that a heating means of one size may be 16 removed and replaced by a heating means of another size.

11. The combination of claim 1 and wherein said supply means includes a guide rod over which the 'filmextends at the rear of a tray on said support means, and a finger assembly carried by said guide rod and extending therefrom beneath a sheet of film to support the latter in readiness to be grasped by the operator to be pulled over a tray on said support means.

12. The combination of claim 1 and wherein said support means includes a platen, a platesituated beneath said platen to carry the same and extending beyond said platen, a Teflon sheet covering said platen and extending around a peripheral edge of said plate, and an elongated,

channel assembly receiving said edge of said plate, ex:

tending along said edge, and clamping said sheet to said: edge, said channel assembly being composedof a plurality of sections situated in end-to-end relation, and re-,

leasable spring means holding said sectionstogether. so that by way of said spring means the channel assembly can be removed from said plate.,, 1

13. The combination of claim 1 and wherein a spring means coacts with said manually operable means for yieldably maintaining the latter in said rest position thereof and for returning saidmanually operable means to said rest position upon release of said manually operable means after the operator has displaced said manually operable means in opposition to said spring means through said working stroke thereof, and latch means carried in part by said support means and in part by said manually operable means to be manipulated by the operator for releasably latching said manually operable means in said operating position thereof.

14. The combination of claim 1 and wherein said heating means is of an endless configuration for surrounding a tray when said manually operable means is in said operating position thereof to burn through the film which extends from the tray, said manually operable means removably supporting said heating means so that a heating means of one size may be replaced by a heating means of a diiferent size, said heating means including an electrical heating element and an electrical connecting structure, and said manually operable means carrying an electrical structure which coacts with that of said heating means when the latter is mounted on said manually operable means for supplying energy thereto.

References Cited UNITED STATES PATENTS Re. 24,396 11/1957 Rumsey 53-390 X 2,958,172 11/1960 Branche 53--141 3,017,729 1/1962 Cheeley 53184 X 3,093,944 6/ 1963 Arvidson 53390 X 3,204,384 9/1965 Dallas 53141 X 3,295,295 1/ 1967 Stewart 5 3390 3,323,282 6/1967 Duns.

3,330,094 7/1967 Ford 53-184 X 3,378,991 4/ 1968 Anderson.

3,402,874 9/1968 Sternau 53-184 X 3,408,245 10/ 1968 Beason.

3,412,527 11/1968 Aquarius 53-390,

3,406,612 10/1968 Terzuoli 93-1 3,423,901 1/ 1969 Peppler 53184 X 3,427,729 2/1969 Piazze 53184 X WAYNE A. MORSE, JR., Primary Examiner US. (:1. X;R. 53-184, 389; 93-1, 5;; 

